In the related technologies, in order to meet the requirement of high rate, the concept of multi-carrier is introduced into the system.
The base station can be configured with a plurality of carriers that can be classified into two types: one type is a fully-configured carrier, and the other type is a partially-configured carrier, wherein the fully-configured carrier includes all indispensable system side information such as synchronization channel, control channel and the like, and the partially-configured carrier may only include a data transport channel or only include some indispensable control messages. Compared with the fully-configured carrier, the partially-configured carrier may not include the synchronization channel.
At the terminal side, the carriers can be classified into a primary carrier and a secondary carrier.
In the above, the primary carrier necessarily is a fully-configured carrier mainly used for the interaction of the control messages and/or data between the base station and the terminal, and also used for performing the interaction of service processing, and Physics (PHY for short) control information or Media Access Control (MAC for short) information; in addition, the primary carrier also can be used for completing part of the terminal control functions, such as network access. It should be indicated that each terminal has one and only one primary carrier in one cell.
The secondary carrier, which can be either a fully-configured carrier or a partially-configured carrier, is an additional carrier for transmitting services for the terminal and is mainly used for the data interaction, wherein the secondary carrier also can carry the control signaling that supports the multi-carrier operation. One terminal can have one or more secondary carriers and may not have any secondary carrier.
In the mobile communication system, when the terminal moves to the edge of the base station, if the signal condition of the original serving base station declines, and it cannot continue to provide services for the terminal, the terminal then needs to switch to another base station to maintain the continuity of the services. This kind of switch is an inter-base station switch.
In the multi-carrier system, as one base station is provided with a plurality of carriers, when the load of the carrier (serving carrier) currently used by the terminal is too large so that a Quality of Service (QoS for short) is caused to decline or the signal strength of the serving carrier decreases so that the terminal needs to search for the carrier with better strength, the terminal can switch onto another carrier in the base station to perform the data transmission. This kind of switch is an intra-base station switch.
In a single-carrier system, the base station merely has one carrier and will broadcast the information of this carrier through the broadcasting information. However, in the multi-carrier system, one base station is configured with a plurality of carriers that are carried on different frequencies, therefore, when the terminal performs the intra- or inter-base station switch, the plurality of carriers should be scanned according to the information such as frequency and bandwidth of each carrier. But when the scan is completed, the terminal currently does not have corresponding solution for sending a multi-carrier scan report to the base station.